The carboxylic esters of aliphatic sulphocarboxylic acids containing up to eight carbon atoms in the molecule with aliphatic or cycloaliphatic, mono or polyhydric alcohols containing more than eight carbon atoms are stated to be emulsifying agents. They may be prepared (a) from the sulphocarboxylic acids by heating substantially an equimolecular proportion of the latter or of the corresponding mono alkali salt with the alcohol, (b) from the carboxylic esters of the sulphocarboxylic acids with alcohols containing up to eight carbon atoms by treating the alkali salts of the latter with the alcohols containing more than eight carbon atoms, (c) from esters of aliphatic carboxylic acids containing up to eight carbon atoms and at least one double bond with alcohols containing more than eight carbon atoms by sulphonation with more than one molecular proportion of a sulphonating agent stronger than sulphuric acid monohydrate, (d) from esters of aliphatic carboxylic acids containing up to eight carbon atoms and at least one halogen atom with alcohols containing more than eight carbon atoms by treatment with alkali metal, alkaline-earth metal or heavy metal sulphites or with alkali hydrosulphides followed by oxidation. Instead of the alcohols themselves, substituted derivatives may be used, such as their halogen or carboxylic acid derivatives. The following alcohols and derivatives are mentioned: dodecyl, octodecyl and olein alcohols, octodecanediol, the alcohols obtained by reduction of animal and vegetable fats and oils and of resinic, naphthenic and montanic acids, the alcohols obtained by oxidation of paraffin oil or wax, dichloroctodecyl alcohol, ricinoleic acid, alcohol-ethers prepared by introducing alkyl or cycloalkyl groups into one hydroxy group of polyhydric alcohols, such as propyleneglycolmonooctodecylether and butyleneglycolmonohexylether, which may be prepared from the corresponding alkylene oxide and alcohol. Sulphoacetic, a -sulphopropionic, sulpho-iso-butyric and sulphovaleric acids are specified, and the following non-sulphonated acids: crotonic, dimethylacrylic, monochloracetic and a -brompropionic acids. Unsubstituted carboxylic acids may also be used, and halogens introduced after they have been esterified. The sulphonating agents stronger than sulphuric acid are, sulphur trioxide, oleum of at least 23 per cent strength, chlorsulphonic acid and mixtures of monohydrate with organic acid anhydrides. Organic diluents, surface active catalysts, e.g. charcoal or bleaching earths and dehydrating agents, e.g. phosphorous pentoxide may be used during the sulphonation. Products containing more than one sulphonic group may be obtained by sulphonating the esters prepared from sulphocarboxylic acids or by starting with polyhalogen carboxylic acids. The products may be used alone or in association with salts, sodium perborate, dilute acids, e.g. hydrochloric or acetic acid, glue, solvents, e.g. carbontetrachloride, cyclohexanol, turpentine or mineral, vegetable or animal oils. In examples: (1) sulphoacetic acid or its monosodium salt is esterified with octodecyl or olein alcohol or the alcohol mixture obtained by the catalytic reduction of coco nut oil: (2) chloracetic acid is esterified with the alcohol mixture obtained by the catalytic reduction of coco nut oil, octodecanediol and also with ricinoleic acid, and the products boiled with aqueous sodium sulphite in the presence of ethyl alcohol: (3) crotonic acid is esterified with the alcohol mixture obtained by the catalytic reduction of coco nut oil and then sulphonated with a mixture of sulphuric acid and acetic anhydride.ALSO:The carboxylic esters of aliphatic sulphocarboxylic acids containing up to eight carbon atoms in the molecule with aliphatic or cycloaliphatic, mono or polyhydric alcohols containing more than eight carbon atoms are stated to be wetting, cleansing and emulsifying agents. They may be prepared (a) from the sulphocarboxylic acids by heating substantially an equimolecular proportion of the latter or of the corresponding mono alkali salt with the alcohol; (b) from the carboxylic esters of the sulphocarboxylic acids with alcohols containing up to eight carbon atoms by treating the alkali salts of the latter with the alcohols containing more than eight carbon atoms; (c) from esters of aliphatic carboxylic acids containing up to eight carbon atoms and at least one double bond with alcohols containing more than eight carbon atoms by sulphonation with more than one molecular proportion of a sulphonating agent stronger than sulphuric acid monohydrate; (d) from esters of aliphatic carboxylic acids containing up to eight carbon atoms and at least one halogen atom with alcohols containing more than eight carbon atoms by treatment with alkali metal, alkaline earth metal or heavy metal sulphites or with alkali hydrosulphides followed by oxidation. Instead of the alcohols themselves, substituted derivatives may be used, such as their halogen or carboxylic acid derivatives. The following alcohols and derivatives are mentioned; dodecyl, octodecyl and olein alcohols, octodecanediol, the alcohols obtained by reduction of animal and vegetable fats and oils and of resinic, naphthenic and montanic acids, the alcohols obtained by oxidation of paraffin oil or wax, dichloroctodecyl alcohol, ricinoleic acid, alcohol-ethers prepared by introducing alkyl or cycloalkyl groups into one hydroxy group of polyhydric alcohols, such as propyleneglycolmonooctodecylether and butyleneglycolmonohexylether, which may be prepared from the corresponding alkylene oxide and alcohol. Sulphoacetic, a -sulphopropionic, sulpho-iso-butyric and sulphovaleric acids are specified, and the following non-sulphonated acids: crotonic, dimethylacrylic, monochloracetic and a -brompropionic acids. Unsubstituted carboxylic acids may also be used, and halogens introduced after they have been esterified. The sulphonating agents stronger than sulphuric acid are, sulphur trioxide, oleum of at least 23 per cent strength, chlorsulphonic acid and mixtures of monohydrate with organic acid anhydrides. Organic diluents, surface-active catalysts, e.g. charcoal or bleaching earths and dehydrating agents, e.g. phosphorus pentoxide may be used during the sulphonation. Products containing more than one sulphonic group may be obtained by sulphonating the esters prepared from sulphocarboxylic acids or by starting with polyhalogen carboxylic acids. The products may be used alone or in association with salts, sodium perborate, dilute acids, e.g. hydrochloric or acetic acid, glue, solvents, e.g. carbontetrachloride, cyclohexanol, turpentine or mineral, vegetable or animal oils. In examples: (1) sulphoacetic acid or its monosodium salt is esterified with octodecyl or olein alcohol or the alcohol mixture obtained by the catalytic reduction of coconut oil; (2) chloracetic acid is esterified with the alcohol mixture obtained by the catalytic reduction of coconut oil, octodecanediol and also with ricinoleic acid, and the products boiled with aqueous sodium sulphite in the presence of ethyl alcohol; (3) crotonic acid is esterified with the alcohol mixture obtained by the catalytic reduction of coconut oil and then sulphonated with a mixture of sulphuric acid and acetic anhydride. The alkali salts of the carboxylic esters of the aliphatic sulphocarboxylic acids may be prepared by saturating with hydrochloric acid a solution or suspension in an alcohol containing eight or less carbon atoms in the molecule of the alkali salts of the acids, neutralizing with barium carbonate, and converting the resulting barium salts into the alkali salts by means of alkali carbonate. Specifications 348,040, 364,107, and 366,909 are referred to.